There are many applications in academic, industrial, and medical fields, as well as others, that may benefit from devices and methods that are capable of accurately and controllably delivering fluids, including liquids and gases that have a beneficial effect when administered in known and controlled quantities. This may be particularly true in the medical field where much of the treatment for a large percentage of patients includes the administration of a known amount of a substance at predetermined intervals. The treatment of diabetes often involves just such a regimented dosage of materials, in particular, the administration of insulin. In addition, the administration of insulin for a diabetic patient is one of a few medical indications wherein the patient routinely administers the medicament to themselves by a subcutaneous modality, such as a hypodermic syringe injection. As such, providing a patient with the means to safely, reliably and comfortably administer required doses of medication may be particularly important in order to facilitate patient compliance and accurate treatment of the condition.
Blood glucose is an important factor for metabolism and the provision of energy and proper organ functioning in mammals. The accurate regulation of blood glucose is, therefore, an essential task necessary for the well being of the mammal. For instance, the neurons of the brain of an organism depend on glucose for fueling their functioning. Hence, blood glucose levels are typically regulated by feedback loops between the brain and the pancreas. The pancreas functions in response to various hormones released by the brain by itself releasing hormones that regulate the uptake, e.g., storage, of blood sugar, or the release of stored blood sugar. For instance, two essential hormones in the regulation of blood sugar levels are insulin and glucagon, both of which are synthesized by specialized cells in the pancreas. Specifically, the β cells of the islets of Langerhans function to synthesize insulin, while the α cells of the islets of Langerhans function to synthesize glucagon.
Maintaining appropriate blood glucose homeostasis is an important factor for promoting the length and quality of life. However, there are many factors that affect the body's ability to maintain such homeostasis. For instance, factors such as the body's ability to produce or respond to insulin, one's physiological condition and/or health, the quantity and type of food one eats, one's metabolic rate, activity level, the types of activities and the exertion level in which one engages, as well as other such factors that make up a person's daily life and/or routine, all play important roles in effecting the body's ability to maintain homeostasis.
Continuous subcutaneous insulin injection and/or infusion therapy is initiated for the replacement of insulin and thereby the treatment of diabetes. Such therapy may include the regular and/or continuous injection or infusion of insulin into the skin of a person suffering from diabetes. Injection is the traditional and most common method for administering insulin. Typically the diabetic will measure his or her blood glucose level, and depending on the level thereof may prepare a syringe or injection pen with insulin to be injected transdermally into the body. However, recently, insulin injecting pumps have been developed for the administration of insulin for those suffering from both type I and II diabetes. Insulin pumps are medical devices used for the administration of insulin in the treatment of diabetes and offer an alternative to multiple daily injections of insulin by an insulin syringe or an insulin pen. They also allow for continuous insulin therapy.
There are, however, several drawbacks associated with the use of subcutaneous injection syringes and/or some currently available infusion pumps for the delivery of insulin. Patient compliance, for instance, is a major problem with respect to the use of insulin syringes. A high percent of subjects suffering from diabetes experience dread when it comes to insulin injections due to the anxiety and discomfort associated with regular use of a the needle therefore. Further complications involve the cost of the syringes, which cost may lead to the spread of infections and diseases, such as human immunodeficiency virus (H IV) and hepatitis, through the sharing and/or reusing of needles. In addition, diabetes patients who choose to use commercially available pumps to avoid the disadvantages of syringe delivery often find that wearing them together with their required infusion set tubing is uncomfortable or unwieldy, particularly while participating in sporting activities or while sleeping.
Some commercially available pumps are designed to be smaller than others, but typically include a patch type element that may be adhered directly to the skin. Such a pump may contain the insulin reservoir, pumping mechanism, power supply as well as an infusion set and automated insert. The patch may be quite a bit heavier than typical infusion set patches. This may pose the problem of the infusion set slowly being pulled out of the patient due to the weight of the patch itself resulting in waste and inaccuracies in treatment. Once the patch is inadvertently knocked off the skin or loosened there may be no means to reinsert the infusion set also resulting in waste and added expense.
Furthermore, the smaller the size of an infusion pump, the more difficult it is for a patient to interface with the device. Commercially available pumps typically have a single screen and one or more hard buttons for enabling a user to navigate through multiple menus and screens. A drawback of requiring a user to navigate through multiple menus and pages to set up a delivery of insulin may be that the user finds the process too complex and time consuming to properly use the infusion device to its fullest potential. As a result, some users tend to “set-it and forget-it”.
Generally a patient's insulin requirements vary greatly, as mentioned above, and may be influenced by a variety of factors (e.g., caloric intake, physiological conditions). Therefore, there is a need for a user friendly portable infusion device that has the ability to tailor appropriate insulin delivery profiles to a user. There is also a need for an infusion device providing an interface that facilitates its use.